Five years after completing the 500-megawatt (MW) Astoria Energy natural gas combined-cycle power plant in Queens, N.Y., E-J Electric Installation Co. of Long Island City, N.Y., is at work on its twin—Astoria Energy Phase II—helping usher in New York’s cleanest, most efficient power plant.
Astoria Energy LLC built the second 500-MW natural gas plant in Queens in 2009 and 2010 as part of a plan to provide more power more efficiently to residential, commercial and government customers in the New York metropolitan area. The Phase II Astoria plant replaces the recently decommissioned Charles Poletti Power Project, located at an adjacent Queens site on the bank of the East River.
E-J Electric has considerable experience in the area—not only has it been constructing Phase II of the Astoria plant, it also constructed Astoria Phase I and the NYPA500 plant, all within a mile of each other.
The inner workings
Once the work is complete, in summer 2011, the second phase of the Astoria plant will be fully operational and will boast many of the same features as Phase I. Phase I, located on a 7-acre lot and costing $650 million to build, includes two combustion turbines and a steam turbine, and it generates 500 MW of power, which is sold to New York utility company Con Edison. Commercial and population growth in the area requires further expansion of power production, which necessitated construction of the second phase, now at hand, with two more combustion turbines, two heat recovery steam generators (HRSGs), and an additional steam turbine-generator.
Like the NYPA500 plant, these two sections of the Astoria Energy plant use both natural gas and fuel oil to generate power for the turbine generators. The exhaust from that process is routed through the heat-recovery steam generators, which boil water to create steam. That steam drives an additional turbine generator to produce more power.
By using an air-cooled condenser (ACC), the plant eliminates the need to take water from the East River as some less environmentally friendly plants do. The turbine generators, in both phases, are housed in a 97,000-square-foot, steel-framed structure, which includes 25,000 cubic yards of structural concrete.
While Phase II takes place on property adjoining Phase I, the two facilities will operate independently. Still, a single control room that initially managed operations of the first phase now will oversee operations of both. E-J Electric had constructed the new control room for the Phase I facility, and the company has now refurbished and expanded it with an extension to share with all Phase II equipment. Additionally, two load-commutated inverters (LCI), one in each phase, tie the two phases together, and each one is capable of starting all four turbines (at both the Phase I and Phase II plants).
Behind the scenes with E-J
E-J Electric provided design/assist services for the high- and low-voltage power at Phase II, with a total of 15 separate contracts for various tasks, which includes power to the plant itself, construction of a substation, and security and life safety systems, said Brendon Bergin, senior project manager. Before work began, E-J’s engineering group participated in early planning sessions with the EPC contractor, SNC Lavalin, to create field routing plans.
The on-site work for E-J Electric began with building temporary services for the construction crew. E-J Electric then prepared the underground electrical duct banks from June until December 2009. The underground ducts—90,000 feet worth—feed power to the entire site. Once underground piping was installed, E-J took on aboveground work in March 2010.
Turbines and all of their accessory skids (the centerline equipment) were towed to the site by barge on the East River. These were set on building slabs, along with the generator circuit breakers, prior to construction of the turbine building, which commenced in January 2010.
In March, the main electrical switchgear installation began. The plant is a “two over one” design with two gas turbines and one steam turbine that send power through 18-kilovolt (kV) isolated phase bus duct to three general setup (GSU) transformers and two auxiliary transformers. The auxiliaries convert the power to 5 kV, which is used to feed large pumps and gas compressors and is stepped down to 480 volts (V) to feed the balance-of-plant equipment.
From the GSU transformers, E-J Electric installed three sets of underground 345-kV solid dielectric cables to transmit the power to an ABB gas insulated substation, which the company was erecting simultaneously. From the substation, E-J Electric’s overhead line crew installed a 345-kV overhead transmission line to deliver the power to another 345-kV GIS and switchyard being built nearly a mile away.
In March 2010, E-J electricians began putting together the second substation to take the power back to the Con Edison grid. This was a unique element to Phase II; the Phase I project has no 345 kV substation and instead feeds power through a 138 kV switchyard to the Con Edison utility grid.
Substation work was accomplished under four separate contracts. Underground work for the substation began in April, and underground conduit was laid between that time until about August. E-J electricians then began erecting the gas insulated switchgear (GIS) and switchyard electric system, which continued until November, said project manager John Perrotta.
The GIS consisted of a four circuit breaker ring bus with future capacity for two additional ones. The ring bus serves two Con Edison high-pressure fluid-filled feeders through overhead aerial cables and 6-inch aluminum bus located in the adjacent switchyard. Two 150-MVA shunt reactors were relocated from the decommissioned Poletti Power Project and were installed in the new switchyard.
Testing and commissioning went on until late December, after which the substation was energized for the first time.
In addition to installing all the GIS and switchyard power distribution equipment, E-J Electric also installed all associated controls, instrumentation, and metering. E-J Electric’s scope also included a complete fit-out of all building services including lighting, power, mechanical, building management systems, security, fire alarm and communications.
Once the substation went live, power then was connected to Phase II through the 345-kV aerial transmission line.
Planning for the challenges
According to Thomas Kregel, project executive, working with an extremely aggressive schedule and almost no staging area was challenging.
“It’s a tight, constrained site,” said Chuck McCall, Astoria Energy CEO. “At the end of the day, there [isn’t] any laydown area, and that presents some unique challenges.”
To make it work, the contractors and subcontractors made planning the cornerstone of the project.
“The biggest challenge has been the schedule and logistics,” Perrotta said.
For example, throughout the project, E-J electricians worked around the Phase I portion of the plant’s scheduled outages, first to tie in the control room as the plant was shut down for maintenance, and a second time to tie the LCI together with a feeder from the electrical room to run other startup equipment.
“We plan our work activities around the scheduled outages in order to minimize client down time,” Bergin said.
The outages lasted between a few days to a week. In some cases, the outages were extended to ensure the work was done, McCall said, adding that in that case, Astoria Phase II compensated Astoria Phase I for the down time.
“We’ve managed to keep those outage extensions to a minimum,” he said.
Because of tight space, Kregel said, the contractors worked with just-in-time deliveries, often receiving cable in the afternoon and then pulling it that night. The men worked in two shifts, with 250 men at peak, among all of the 15 projects underway.
Although E-J Electric has constructed several power stations, this one stands out, Kregel said, because the tight space and schedule required close coordination of suppliers and work, with daily coordination meetings. The EPC contractor, SNC Lavalin, provided an excellent team, which kept the project moving forward, Kregel added.
The project began about 30 days late, but by winter 2011, the crews were back on schedule aiming for the summer startup date. Despite the space and time constraints, McCall said, the contractors have managed to meet schedules due to extensive planning and coordination.
“E-J has collaborated well with the other contractors; they’re doing a great job,” he said.
Seeing it through
About 100 men worked on the switchyard/substation site in two shifts, finishing the bulk of the work over the course of three months. Once the work was complete, E-J Electric had run 20,000 feet of grounding cable, 4,000 feet of underground conduit, 300 feet of cable tray, 450 feet of concrete trough and 20,000 feet of aboveground conduit. In addition, the company ran 40,000 feet of power cable and 120,000 feet of control and instrumentation cable. For the switchyard, electricians installed 1,800 feet of aerial 345-kV cable and 240 feet of 6-inch aluminum bus and a total of 175 welded, 345-kV aluminum fittings.
At the Phase II power plant site, E-J Electric began pulling cable for the generators and water injection system over the summer of 2010 and installed cable tray. The company also began pulling and terminating wire cable to the auxiliary boiler and ammonia system in the fall, ran cable for the chemical feeding system and compressed air system, the high- and low-pressure steam systems, and the condensation system.
By the end of 2010, the company was still operating two eight-hour shifts, while specialized work, such as the 345-kV terminations for the solid dielectric cable, required specific specialty crews who worked single 12-hour shifts to keep the project on schedule.
By the end of the project, E-J had installed 90,000 feet of underground conduit, 10,000 feet of cable tray, 185,000 feet of aboveground conduit, 190,000 feet of power cable, and 620,000 feet of control and instrumentation cable. It also installed 30,000 feet of medium-voltage cable and 40,000 feet of grounding cable.
The plant owners project that Astoria Energy II will decrease nitrogen oxide air emissions 1,222 tons per year and reduce sulfur oxide emissions by 1,542 tons per year—nearly an 18 percent cut in both pollutants—by displacing currently operational in-city power plants, including Queens plants.
SWEDBERG is a freelance writer based in western Washington. She can be reached at email@example.com.